JP2000288973A - Tactile sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a tactile sensor to detect the three-dimensional characteristics of the object to be operated, such as conveyance, assembly, and processing, of a robot and other handling device. SOLUTION: A part of the plane part 9 of the base of a rubber skin 1 is expressed in a manner that the adjoining pins 4 of a plurality of the pins 4 point to a direction in which the pins 4 are opened from each other by an object 5 making contact with the outer surface of a rubber skin 1, and a pattern different in brightness is formed. By detecting the pattern by a camera 2, the three-dimensional characteristics of the object 5 are detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tactile sensor for detecting three-dimensional characteristics of a contact object.

[0002]

2. Description of the Related Art In a conventional tactile sensor, a microswitch simply detects the presence or absence of contact with a contacting object. A pressure-sensitive conductive rubber or a conductive ink sheet is sandwiched between comb-shaped electrodes, and a resistance value of the tactile sensor is measured. There are a method of detecting a pressure distribution from a change, a method of placing a silicone rubber on an optical waveguide plate, and a method of detecting a contact distribution from a light leakage pattern generated by the contact between the optical waveguide plate and the silicon rubber at the time of object contact.

[0003]

When a gripping operation is performed with a fingertip of a robot, different algorithms are applied in accordance with the three-dimensional characteristics of the object in the contact area between the finger and the object. Therefore, as a tactile sensor for a robot, development of a sensor capable of detecting a three-dimensional characteristic of a contact object is desired.

However, the conventional pressure-sensitive sheet-shaped tactile sensor using the above-mentioned conventional pressure-sensitive conductive rubber or conductive ink,
Each of the optical waveguide type tactile sensors detects a one- or two-dimensional feature of a contact object, and cannot obtain information on a pressing direction. For this reason, when the contact object has a three-dimensional curved surface, or when a sensor is provided on a curved object such as a fingertip of a multi-fingered hand, the contact area between the sensor and the contact object becomes small, and the characteristics of the contact object are reduced. There was a problem that could not be detected.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to ensure sufficient flexibility in the pushing direction in contact with an object so that the contact object can be three-dimensionally deformed from its biting deformation. An object of the present invention is to realize a tactile sensor for detecting a characteristic feature.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a rubber skin, a camera and lighting,
A tactile sensor for detecting a three-dimensional shape of an abutting object, wherein the rubber skin includes a base and a plurality of small pins arranged on an inner surface of the base on the camera side, and the base and the small plurality of pins are arranged. The pins are formed integrally or separately so as to have different reflectivities from each other, and the object in contact with the outer surface of the rubber skin causes the adjacent pins of the plurality of small pins to open each other. The surface of the base of the rubber skin is partially exposed to form a pattern having different brightness and a pin array pattern, and the three-dimensional shape of the object is detected by detecting the pattern with the camera. A tactile sensor characterized by the above is provided.

[0007] The rubber skin is disposed in a window of a space formed in the fingertip of the robot hand, and the space incorporates an image transmission fiber and an illumination fiber optically coupled to the camera. The tactile sensor may be applied as a configuration in which the distal end of the endoscope tube is disposed so as to face the inner surface of the rubber skin.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a tactile sensor according to the present invention will be described based on embodiments with reference to the drawings. FIG.
FIG. 1 is a diagram illustrating a basic configuration of a tactile sensor according to the present invention. As shown in FIG. 1, the tactile sensor includes a rubber skin 1 as a contact surface, a small camera 2, and a light 3.

The rubber skin 1 has a plurality of small pins 4 on the inner surface on the side where the camera 2 is placed (opposing surface of the camera 2).
Have a pin arrangement. The base of the rubber skin 1 is made of a soft rubber of a color (for example, white) that easily reflects light, and the pin 4 is made of a hard rubber of a color (for example, black) that hardly reflects light. Rubber Skin 1 Base and Pin 4
May be formed integrally or separately.

Next, the operation of the tactile sensor will be described with reference to FIG. When the object 5 to be detected comes into contact with the outer surface of the rubber skin 1 of the tactile sensor, the rubber skin 1 is stretched toward the camera 2 and deforms so as to bite in accordance with the shape of the object 5. According to the three-dimensional shape of the object, such as the corner vertex 6 which is the intersection of the three surfaces of the object 5 and the two edges 7,
The rubber skin 1 has a high curvature.

By the way, the direction of the pin 4 is the rubber skin 1
When the object 5 abuts as described above so as to face the normal direction, in the high curvature area 8 of the rubber skin 1, the directions of the pins 4 adjacent to each other are aligned along the high curvature area 8. A flat portion 9 that is easy to reflect the light of the illumination 3 appears so as to open outward. That is, the brightness pattern changes along the region 8 where the object 4 comes into contact and the curvature of the rubber skin 1 is high.

By capturing the brightness pattern with the small camera 2, the shape of the object 5 can be detected, and its three-dimensional features such as the corner vertex 6 and the edge 7 of the object 5 can be detected. Further, since the direction of the pin is directed outward along the region 8 having a high curvature, the pattern of the direction of the pin also changes. The feature of the object 5 is also detected by capturing the pattern of the direction of the pin with a small camera.

Further, when the surface of the object 5 comes into contact with the rubber skin 1, a region having the same inclination as viewed from the camera (for example, the right surface of the rubber skin 1 in FIG. 2) has the same brightness pattern and the same pin. It becomes a pattern of the direction. Thus, a region belonging to the same surface can be separated from a region belonging to another surface.

FIG. 3 shows an embodiment in which the tactile sensor according to the present invention is applied to a fingertip portion of a multi-fingered hand such as a robot. The distal end of the fingertip 10 has a finger base 12 defining a space 11. The distal end of the endoscope tube 13 is disposed so as to protrude into the space portion 11. This endoscope tube 13
Is a known endoscope tube optically coupled to an imaging device such as a camera provided on the base end side of the robot hand, and incorporates an illumination fiber, an image transmission fiber, and the like.

A window 14 is formed in the finger base 12, and the rubber skin 1 is provided so as to cover the window 14. The rubber skin 1 is disposed such that the surface on which the pin array is formed faces the space 11 and faces the distal end of the endoscope 13. In this manner, the space 11 defined by the finger base 12 and the rubber skin 1 is filled with a transparent liquid such as silicone oil.

The fingertip having the tactile sensor of this embodiment is
As shown in FIG. 4, when the user tries to grasp the object 5 and comes into contact with the object 5, the rubber skin 1 is pressed into the space 11 and cut into the contact portion (edge or corner vertex) of the object 5. Dent in. As a result, the pin 4 is pushed open to change the reflection state of the rubber skin flat portion 9 along the contact portion of the object, and this is detected by the endoscope tube 13, and the three-dimensional characteristics of the object 5 are detected. Is detected. The rubber skin 1 and the pin array 4 are formed by laminating two rubbers on the outside and the inside, making only the inside rubber surface hard to reflect light (for example, black), and reflecting the outside rubber and the inside rubber inside the light. It is made by making a notch in the inner rubber in a lattice shape as a color that can be easily made (for example, white).

In the above-described basic configuration and embodiments of the tactile sensor according to the present invention, the base of the rubber skin 1 is made of soft rubber of a color (for example, white) that is easily reflected by light, and the pin 4 is hardly reflected by light. Although it is made of hard rubber of a color (for example, black), it may be formed so that the base is hardly reflected and the pins are easily reflected.

The embodiments of the tactile sensor according to the present invention have been described above. However, the present invention may have various other modes within the scope of the technical idea described in the claims. Needless to say.

[0019]

According to the present invention having the above-described structure, when an object to be detected comes into contact with the rubber skin, the rubber skin is deformed, and the pin between the pins is formed along a portion having a high curvature. Since the base part of the rubber skin is exposed and the pattern of the brightness changes, the change in the pattern of the brightness is captured by a small camera, so that a contact object such as a corner vertex or an edge can be detected.
Dimensional features can be detected.

Further, since the pin faces outside the region having a high curvature, the pattern of the direction of the pin can be captured by a small camera, and three-dimensional characteristics of a contact object such as a corner vertex or an edge can be detected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a tactile sensor according to the present invention.

FIG. 2 is a diagram illustrating the operation of the tactile sensor according to the present invention.

FIG. 3 is a diagram showing an embodiment in which the tactile sensor according to the present invention is applied to a fingertip of a multi-fingered hand.

4 is a diagram illustrating a detection operation when an object comes into contact with the fingertip of the multi-finger hand in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rubber skin 2 Small CCD camera 3 Lighting 4 Projection (pin) 5 Object to be detected 10 Fingertip 11 Space part 12 Finger base part 13 Endoscope tube 14 Window

Claims (2)

[Claims] 1. A tactile sensor having a rubber skin, a camera, and illumination for detecting a three-dimensional characteristic of an abutting object, wherein the rubber skin is arranged on a base and an inner surface of the base on the camera side. The base and the small pins are formed integrally or separately so as to have different reflectances from each other, and the object abutting on the outer surface of the rubber skin includes: A part of the surface of the base of the rubber skin is exposed in such a direction that the pins adjacent to each other of the plurality of small pins are opened to form a pattern having different brightness and a pin arrangement pattern. A tactile sensor characterized in that a three-dimensional feature of the object is detected by detecting the three-dimensional feature. 2. The image processing apparatus according to claim 1, wherein the rubber skin is disposed in a window of a space formed in a fingertip of the robot hand, and an image transmission fiber and an illumination fiber optically coupled to the camera are provided in the space. 2. The tactile sensor according to claim 1, wherein a tip of the built-in endoscope tube is disposed so as to face an inner surface of the rubber skin.